How to control loft behavior

glenn_griffin

I'm new to onshape and CAD in general and trying to model a series of curved funnels. I've watched videos and searched the forums for how this might be done, but most examples are either too straightforward or not applicable to my situation. I've been attempting to use either guides or a path to accomplish what I want, but have run into a variety of errors when trying.

Here is my model: https://cad.onshape.com/documents/478bc7bc3fd0bd0f6bde2534/w/9a7fdbc294e1a68468d25d03/e/0ed833a7ef8403570979428c?renderMode=0&uiState=64436a8995aad670dbc42e14

It's close to what I want, but the loft connections are drawn straight at the connection points and I would like them to curve along with the arc. The current method I have produces sidewalls that are angled as they move up the z axis, which creates a pinch point for items to get stuck as they fall into the funnel. I would like for the sidewalls to gradually slope towards the center while following the arc. The cross-section view below should help illustrate the issue. Any suggestions for how to fix this, or how I might be able to model curves that are usable as guides or a path would be incredibly useful. Thanks.

eric_pesty

I'm not 100% clear what you mean but I think what you want is to play with the "end conditions" on the loft. Specifically try setting the start (assuming it's the slot) to "normal to profile" and adjust the start magnitude

eric_pesty

I was going to add, you might need to use some more "advanced" techniques if this still doesn't get you the shape you want.
possibly using a sweep starting from the midplane along a curve (generated from the arc slot CL and "ramp" up the side for example...

Using "guides" might also be a way to get more control like I did with the longest slot here:
https://cad.onshape.com/documents/603c7cbdc0d1af58698441ee/w/0064452c6ed15c472e06d18a/e/5f365e25198009eeef136922

glen_dewsbury

Not sure what you're expecting either. You can control end conditions if that's what you're looking for. See loft 2 with end conditions as normal to profile and set magnetude as wanted.
https://cad.onshape.com/documents/b629cabda923146d6df8d4d0/w/01f99aa8c9e64f0bc9a7577e/e/fd8812a94d2d017d87ccada2
 

glenn_griffin

Thanks for the examples and for correctly interpreting my poorly worded problem. Using the guides to control the loft is giving me exactly what I want. I had tried it before, but kept getting errors about the guide not touching every profile boundary. Your example showed me how to do that correctly.

glenn_griffin

eric_pesty said:

I was going to add, you might need to use some more "advanced" techniques if this still doesn't get you the shape you want.
possibly using a sweep starting from the midplane along a curve (generated from the arc slot CL and "ramp" up the side for example...

Using "guides" might also be a way to get more control like I did with the longest slot here:
https://cad.onshape.com/documents/603c7cbdc0d1af58698441ee/w/0064452c6ed15c472e06d18a/e/5f365e25198009eeef136922

Thanks for the examples and for correctly interpreting my poorly worded problem. Using the guides to control the loft is giving me exactly what I want. I had tried it before, but kept getting errors about the guide not touching every profile boundary. Your example showed me how to do that correctly.